The use of fibrous structures in absorbent articles such as diapers or feminine hygienic articles is well known in the art. Fibrous structures may be either consolidated, bonded webs, such as nonwoven webs, but can also be unbonded structures, often made of natural fibers such as cellulose fibers or chemically modified cellulose fibers.
Unbonded fibrous structures can for example be used as absorbent cores, wherein the fibers are typically mixed with superabsorbent gelling materials, such as superabsorbent polymer particles. Moreover, such unbonded fibrous structures can be used in so-called liquid acquisition systems overlaying the absorbent core.
With the processes used today for high speed manufacture of fibrous webs for absorbent articles, it is difficult to make unbonded fibrous webs having a relatively low basis weight, such as basis weights below 120 g/m2 as such fibrous webs typically suffer from poor homogeneity, resulting in holes in the web and low web integrity. When used in absorbent articles, holes lead to reduced integrity of the fibrous structure, which can reduce the liquid handling performance of absorbent articles.
Generally, numerous processes are known in the industry for laying down fibers in fibrous structures. One process has been developed by Scan Web. The process is described for example in European Patent Application EP 168 957 A1 and in WO 86/00097 A1. However, up to now this process did not appear to be suitable for manufacturing absorbent articles, if the air-laid fibrous structure is to be made in-line with the manufacture of absorbent article. One reason has been that the fibrous structures produced with the Scan Web process typically have a relatively large width. They cannot be used in absorbent articles without prior cutting and slitting the webs in the longitudinal direction, which is a challenge for unbonded fibrous structures. Simply reducing the width of the available equipment does not meet the throughput requirements with regard to mass flow-rate as required by today's absorbent article production lines.